1. Field of the Invention
The present invention relates to a mold for forming a curved window glass with deeply bent end portions for use as a windshield or rear window of an automobile, etc.
2. Description of the Prior Art
A curved window glass for an automobile has heretofore been produced by heating a glass plate held on a mold into a softened state and allowing it to bend after the curved surface of the mold by the weight of the glass plate of itself.
Recently, it has been desired such a window glass for use as a windshield or a rear window of an automobile that has a gently curved main central portion and opposite end portions deeply bent with a small radius of bend, i.e., sharply and nearly at right angles to the main central portion with a view to increasing the visual range and thereby assuring the safety while improving the riding comfort of the vehicle. The deeply bent end portions are herein used as indicating the end portions of a considerable extension away from the the main central portion (i.e., not shallow).
As disclosed in Japanese Patent No. 58-5851 assigned to the same assignee as this application, a prior art mold for forming a curved window glass with deeply bent end portions is known in which side frames are linked to a stationary main frame in such a manner that each side frame turns in response to a turn of a lever with a weight by an angle larger than that of the lever.
It is also known as disclosed in Japanese Utility Model No. 63-44434 a mold in which side frames are movable toward and away from the main frame and provided with stoppers held engaged with the lateral edges of a glass plate with a view to attaining a symmetrical and therefore dimensional accuracy of the product.
A problem of the former prior art mold is that the glass plate in a heated, softened state is liable to bend or displace upwards away from the mold at the opposite lateral end portions since the lateral end portions are light in weight and therefore lack the pushing forces thereon. Further, in case of a glass plate having a black enamelled peripheral portion for forming a vehicle window glass, the lateral end portions are liable to bend downwards after the upward displacement due to the difference in heat absorption between the black enamelled portion and the transparent portion next thereto.
With the latter prior art mold, the above described upward bending or displacement phenomenon of occurs and cannot be prevented.